Electric-powered wheelchairs improve the mobility of people with physical disabilities, but the problem to deal with certain architectural barriers has not been resolved satisfactorily. In order to solve this problem, a stair-climbing mobility system (SCMS) was developed. This paper presents a practical dynamic control system that allows the SCMS to exhibit a successful climbing process when fa...

Certain problems, notably in computer vision, involve adjusting a set of real-valued labels to satisfy certain constraints. They can be formulated as optimisation problems, using the 'least-disturbance' principle: the minimal alteration is made to the labels that will achieve a consistent labelling. Under certain linear constraints, the solution can be achieved iteratively and in parallel, by h...

Modeling coarticulation in speech has been largely limited to short sequences and/or limited phonetic context. We introduce a methodology for modeling both formant frequency and bandwidth in continuous speech, allowing examination of sentencelevel coarticulation. The model represents continuous trajectories as a combination of overlapping local trajectories, which are represented by a weighted-...

In genetic programming a general consensus is that the population should be as large as practically possible or sensible. In this paper we examine a batch of problems of combinatory logic, previously successfully tackled with genetic programming, which seem to defy this consensus. Our experimental data gives evidence that smaller populations are competitive or even slightly better. Moreover, hi...

Reasoning-based problem solving deals with discrete entities and manipulates these to derive new entities or produce branching behavior in order to discover a solution. This paradigm has some basic difficulties when applied to certain types of problems. Properly constructed arithmetic functions, such as those using our SNAC principles, can do such problems very well. SNAC constructions have con...

We present a method for solving service allocation problems in which a set of services must be allocated to a set of agents so as to maximize a global utility. The method is completely distributed so it can scale to any number of services without degradation. We first formalize the service allocation problem and then present a simple hill-climbing, a global hillclimbing, and a bidding-protocol ...

We consider the problem of minimizing the expected cost of determining the correct value of a binary-valued function when it is costly to inspect the values of its arguments. This type of problem arises in distributed computing, in the design of diagnostic expert systems, in reliability analysis of multi-component systems, and in many other applications. Any feasible solution to the problem can...

A toy optimisation problem is introduced which consists of a ÿtness gradient broken up by a series of hurdles. The performance of a hill-climber and a stochastic hill-climber are computed. These are compared with the empirically observed performance of a genetic algorithm (GA) with and without. The hill-climber with a suuciently large neighbourhood outperforms the stochastic hill-climber, but i...

Multiple threads in SMT processor share resources to increase resource utilization and improve overall performance. At the same time, they compete against each other for the shared resources, causing resource monopolization or underutilization. Therefore, resource scheduling mechanism is important because it determines the throughput as well as fairness of the simultaneously running threads in ...